/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Middleware LLC.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 *
 */
package org.hibernate.dialect;

import java.sql.CallableStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Types;

import org.hibernate.Hibernate;
import org.hibernate.cfg.Environment;
import org.hibernate.dialect.function.NoArgSQLFunction;
import org.hibernate.dialect.function.StandardSQLFunction;
import org.hibernate.util.StringHelper;

/**
 * An SQL dialect for MySQL (prior to 5.x).
 *
 * @author Gavin King
 */
public class MySQLDialect extends Dialect {

	public MySQLDialect() {
		super();
		registerColumnType( Types.BIT, "bit" );
		registerColumnType( Types.BIGINT, "bigint" );
		registerColumnType( Types.SMALLINT, "smallint" );
		registerColumnType( Types.TINYINT, "tinyint" );
		registerColumnType( Types.INTEGER, "integer" );
		registerColumnType( Types.CHAR, "char(1)" );
		registerColumnType( Types.FLOAT, "float" );
		registerColumnType( Types.DOUBLE, "double precision" );
		registerColumnType( Types.DATE, "date" );
		registerColumnType( Types.TIME, "time" );
		registerColumnType( Types.TIMESTAMP, "datetime" );
		registerColumnType( Types.VARBINARY, "longblob" );
		registerColumnType( Types.VARBINARY, 16777215, "mediumblob" );
		registerColumnType( Types.VARBINARY, 65535, "blob" );
		registerColumnType( Types.VARBINARY, 255, "tinyblob" );
		registerColumnType( Types.NUMERIC, "decimal($p,$s)" );
		registerColumnType( Types.BLOB, "longblob" );
//		registerColumnType( Types.BLOB, 16777215, "mediumblob" );
//		registerColumnType( Types.BLOB, 65535, "blob" );
		registerColumnType( Types.CLOB, "longtext" );
//		registerColumnType( Types.CLOB, 16777215, "mediumtext" );
//		registerColumnType( Types.CLOB, 65535, "text" );
		registerVarcharTypes();

		registerFunction("ascii", new StandardSQLFunction("ascii", Hibernate.INTEGER) );
		registerFunction("bin", new StandardSQLFunction("bin", Hibernate.STRING) );
		registerFunction("char_length", new StandardSQLFunction("char_length", Hibernate.LONG) );
		registerFunction("character_length", new StandardSQLFunction("character_length", Hibernate.LONG) );
		registerFunction("lcase", new StandardSQLFunction("lcase") );
		registerFunction("lower", new StandardSQLFunction("lower") );
		registerFunction("length", new StandardSQLFunction("length", Hibernate.LONG) );
		registerFunction("ltrim", new StandardSQLFunction("ltrim") );
		registerFunction("ord", new StandardSQLFunction("ord", Hibernate.INTEGER) );
		registerFunction("quote", new StandardSQLFunction("quote") );
		registerFunction("reverse", new StandardSQLFunction("reverse") );
		registerFunction("rtrim", new StandardSQLFunction("rtrim") );
		registerFunction("soundex", new StandardSQLFunction("soundex") );
		registerFunction("space", new StandardSQLFunction("space", Hibernate.STRING) );
		registerFunction("ucase", new StandardSQLFunction("ucase") );
		registerFunction("upper", new StandardSQLFunction("upper") );
		registerFunction("unhex", new StandardSQLFunction("unhex", Hibernate.STRING) );

		registerFunction("abs", new StandardSQLFunction("abs") );
		registerFunction("sign", new StandardSQLFunction("sign", Hibernate.INTEGER) );

		registerFunction("acos", new StandardSQLFunction("acos", Hibernate.DOUBLE) );
		registerFunction("asin", new StandardSQLFunction("asin", Hibernate.DOUBLE) );
		registerFunction("atan", new StandardSQLFunction("atan", Hibernate.DOUBLE) );
		registerFunction("cos", new StandardSQLFunction("cos", Hibernate.DOUBLE) );
		registerFunction("cot", new StandardSQLFunction("cot", Hibernate.DOUBLE) );
		registerFunction("crc32", new StandardSQLFunction("crc32", Hibernate.LONG) );
		registerFunction("exp", new StandardSQLFunction("exp", Hibernate.DOUBLE) );
		registerFunction("ln", new StandardSQLFunction("ln", Hibernate.DOUBLE) );
		registerFunction("log", new StandardSQLFunction("log", Hibernate.DOUBLE) );
		registerFunction("log2", new StandardSQLFunction("log2", Hibernate.DOUBLE) );
		registerFunction("log10", new StandardSQLFunction("log10", Hibernate.DOUBLE) );
		registerFunction("pi", new NoArgSQLFunction("pi", Hibernate.DOUBLE) );
		registerFunction("rand", new NoArgSQLFunction("rand", Hibernate.DOUBLE) );
		registerFunction("sin", new StandardSQLFunction("sin", Hibernate.DOUBLE) );
		registerFunction("sqrt", new StandardSQLFunction("sqrt", Hibernate.DOUBLE) );
		registerFunction("tan", new StandardSQLFunction("tan", Hibernate.DOUBLE) );

		registerFunction("radians", new StandardSQLFunction("radians", Hibernate.DOUBLE) );
		registerFunction("degrees", new StandardSQLFunction("degrees", Hibernate.DOUBLE) );

		registerFunction("ceiling", new StandardSQLFunction("ceiling", Hibernate.INTEGER) );
		registerFunction("ceil", new StandardSQLFunction("ceil", Hibernate.INTEGER) );
		registerFunction("floor", new StandardSQLFunction("floor", Hibernate.INTEGER) );
		registerFunction("round", new StandardSQLFunction("round") );

		registerFunction("datediff", new StandardSQLFunction("datediff", Hibernate.INTEGER) );
		registerFunction("timediff", new StandardSQLFunction("timediff", Hibernate.TIME) );
		registerFunction("date_format", new StandardSQLFunction("date_format", Hibernate.STRING) );

		registerFunction("curdate", new NoArgSQLFunction("curdate", Hibernate.DATE) );
		registerFunction("curtime", new NoArgSQLFunction("curtime", Hibernate.TIME) );
		registerFunction("current_date", new NoArgSQLFunction("current_date", Hibernate.DATE, false) );
		registerFunction("current_time", new NoArgSQLFunction("current_time", Hibernate.TIME, false) );
		registerFunction("current_timestamp", new NoArgSQLFunction("current_timestamp", Hibernate.TIMESTAMP, false) );
		registerFunction("date", new StandardSQLFunction("date", Hibernate.DATE) );
		registerFunction("day", new StandardSQLFunction("day", Hibernate.INTEGER) );
		registerFunction("dayofmonth", new StandardSQLFunction("dayofmonth", Hibernate.INTEGER) );
		registerFunction("dayname", new StandardSQLFunction("dayname", Hibernate.STRING) );
		registerFunction("dayofweek", new StandardSQLFunction("dayofweek", Hibernate.INTEGER) );
		registerFunction("dayofyear", new StandardSQLFunction("dayofyear", Hibernate.INTEGER) );
		registerFunction("from_days", new StandardSQLFunction("from_days", Hibernate.DATE) );
		registerFunction("from_unixtime", new StandardSQLFunction("from_unixtime", Hibernate.TIMESTAMP) );
		registerFunction("hour", new StandardSQLFunction("hour", Hibernate.INTEGER) );
		registerFunction("last_day", new StandardSQLFunction("last_day", Hibernate.DATE) );
		registerFunction("localtime", new NoArgSQLFunction("localtime", Hibernate.TIMESTAMP) );
		registerFunction("localtimestamp", new NoArgSQLFunction("localtimestamp", Hibernate.TIMESTAMP) );
		registerFunction("microseconds", new StandardSQLFunction("microseconds", Hibernate.INTEGER) );
		registerFunction("minute", new StandardSQLFunction("minute", Hibernate.INTEGER) );
		registerFunction("month", new StandardSQLFunction("month", Hibernate.INTEGER) );
		registerFunction("monthname", new StandardSQLFunction("monthname", Hibernate.STRING) );
		registerFunction("now", new NoArgSQLFunction("now", Hibernate.TIMESTAMP) );
		registerFunction("quarter", new StandardSQLFunction("quarter", Hibernate.INTEGER) );
		registerFunction("second", new StandardSQLFunction("second", Hibernate.INTEGER) );
		registerFunction("sec_to_time", new StandardSQLFunction("sec_to_time", Hibernate.TIME) );
		registerFunction("sysdate", new NoArgSQLFunction("sysdate", Hibernate.TIMESTAMP) );
		registerFunction("time", new StandardSQLFunction("time", Hibernate.TIME) );
		registerFunction("timestamp", new StandardSQLFunction("timestamp", Hibernate.TIMESTAMP) );
		registerFunction("time_to_sec", new StandardSQLFunction("time_to_sec", Hibernate.INTEGER) );
		registerFunction("to_days", new StandardSQLFunction("to_days", Hibernate.LONG) );
		registerFunction("unix_timestamp", new StandardSQLFunction("unix_timestamp", Hibernate.LONG) );
		registerFunction("utc_date", new NoArgSQLFunction("utc_date", Hibernate.STRING) );
		registerFunction("utc_time", new NoArgSQLFunction("utc_time", Hibernate.STRING) );
		registerFunction("utc_timestamp", new NoArgSQLFunction("utc_timestamp", Hibernate.STRING) );
		registerFunction("week", new StandardSQLFunction("week", Hibernate.INTEGER) );
		registerFunction("weekday", new StandardSQLFunction("weekday", Hibernate.INTEGER) );
		registerFunction("weekofyear", new StandardSQLFunction("weekofyear", Hibernate.INTEGER) );
		registerFunction("year", new StandardSQLFunction("year", Hibernate.INTEGER) );
		registerFunction("yearweek", new StandardSQLFunction("yearweek", Hibernate.INTEGER) );

		registerFunction("hex", new StandardSQLFunction("hex", Hibernate.STRING) );
		registerFunction("oct", new StandardSQLFunction("oct", Hibernate.STRING) );

		registerFunction("octet_length", new StandardSQLFunction("octet_length", Hibernate.LONG) );
		registerFunction("bit_length", new StandardSQLFunction("bit_length", Hibernate.LONG) );

		registerFunction("bit_count", new StandardSQLFunction("bit_count", Hibernate.LONG) );
		registerFunction("encrypt", new StandardSQLFunction("encrypt", Hibernate.STRING) );
		registerFunction("md5", new StandardSQLFunction("md5", Hibernate.STRING) );
		registerFunction("sha1", new StandardSQLFunction("sha1", Hibernate.STRING) );
		registerFunction("sha", new StandardSQLFunction("sha", Hibernate.STRING) );

		registerFunction( "concat", new StandardSQLFunction( "concat", Hibernate.STRING ) );

		getDefaultProperties().setProperty(Environment.MAX_FETCH_DEPTH, "2");
		getDefaultProperties().setProperty(Environment.STATEMENT_BATCH_SIZE, DEFAULT_BATCH_SIZE);
	}

	protected void registerVarcharTypes() {
		registerColumnType( Types.VARCHAR, "longtext" );
		registerColumnType( Types.VARCHAR, 255, "varchar($l)" );
	}

	public String getAddColumnString() {
		return "add column";
	}
	
	public boolean qualifyIndexName() {
		return false;
	}

	public boolean supportsIdentityColumns() {
		return true;
	}
	
	public String getIdentitySelectString() {
		return "select last_insert_id()";
	}

	public String getIdentityColumnString() {
		return "not null auto_increment"; //starts with 1, implicitly
	}

	public String getAddForeignKeyConstraintString(
			String constraintName, 
			String[] foreignKey, 
			String referencedTable, 
			String[] primaryKey, boolean referencesPrimaryKey
	) {
		String cols = StringHelper.join(", ", foreignKey);
		return new StringBuffer(30)
			.append(" add index ")
			.append(constraintName)
			.append(" (")
			.append(cols)
			.append("), add constraint ")
			.append(constraintName)
			.append(" foreign key (")
			.append(cols)
			.append(") references ")
			.append(referencedTable)
			.append(" (")
			.append( StringHelper.join(", ", primaryKey) )
			.append(')')
			.toString();
	}

	public boolean supportsLimit() {
		return true;
	}
	
	public String getDropForeignKeyString() {
		return " drop foreign key ";
	}

	public String getLimitString(String sql, boolean hasOffset) {
		return new StringBuffer( sql.length() + 20 )
				.append( sql )
				.append( hasOffset ? " limit ?, ?" : " limit ?" )
				.toString();
	}

	public char closeQuote() {
		return '`';
	}

	public char openQuote() {
		return '`';
	}

	public boolean supportsIfExistsBeforeTableName() {
		return true;
	}

	public String getSelectGUIDString() {
		return "select uuid()";
	}

	public boolean supportsCascadeDelete() {
		return false;
	}
	
	public String getTableComment(String comment) {
		return " comment='" + comment + "'";
	}

	public String getColumnComment(String comment) {
		return " comment '" + comment + "'";
	}

	public boolean supportsTemporaryTables() {
		return true;
	}

	public String getCreateTemporaryTableString() {
		return "create temporary table if not exists";
	}
	
	public String getDropTemporaryTableString() {
		return "drop temporary table";
	}

	public Boolean performTemporaryTableDDLInIsolation() {
		// because we [drop *temporary* table...] we do not
		// have to perform these in isolation.
		return Boolean.FALSE;
	}

	public String getCastTypeName(int code) {
		if ( code==Types.INTEGER ) {
			return "signed";
		}
		else if ( code==Types.VARCHAR ) {
			return "char";
		}
		else if ( code==Types.VARBINARY ) {
			return "binary";
		}
		else {
			return super.getCastTypeName( code );
		}
	}

	public boolean supportsCurrentTimestampSelection() {
		return true;
	}

	public boolean isCurrentTimestampSelectStringCallable() {
		return false;
	}

	public String getCurrentTimestampSelectString() {
		return "select now()";
	}

	public int registerResultSetOutParameter(CallableStatement statement, int col) throws SQLException {
		return col;
	} 
	
	public ResultSet getResultSet(CallableStatement ps) throws SQLException {
		boolean isResultSet = ps.execute(); 
		while (!isResultSet && ps.getUpdateCount() != -1) { 
			isResultSet = ps.getMoreResults(); 
		} 
		return ps.getResultSet();
	}

	public boolean supportsRowValueConstructorSyntax() {
		return true;
	}


	// Overridden informational metadata ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

	public boolean supportsEmptyInList() {
		return false;
	}

	public boolean areStringComparisonsCaseInsensitive() {
		return true;
	}

	public boolean supportsLobValueChangePropogation() {
		// note: at least my local MySQL 5.1 install shows this not working...
		return false;
	}

	public boolean supportsSubqueryOnMutatingTable() {
		return false;
	}
}